We have used a conventional scanning tunneling microscope (STM) as well as a combined scanning tunneling-atomic force microscope (STM-AFM) to probe tunneling characteristics of gold films in air. Both instruments yield current-voltage measurements that frequently exhibit sudden changes. In addition, STM and STM-AFM measurements reveal associated discrete changes in barrier height and in tip-sample forces, respectively. We propose that these phenomena can be attributed to charge trapping/detrapping events that are mediated by molecules present in the tunnel junction.
Physical Review B
- Pub Date:
- June 2002
- Other topics in electronic structure and electrical properties of surfaces interfaces thin films and low-dimensional structures;
- Scanning tunneling microscopy;
- Scanning tunneling and atomic force microscopy